Regarding adding B-29 to Aces High, read the book Flyboys.
B-29 didn't work that well at high alt and in Japan's jetstream. When it came down low, it was in such large numbers against such beaten opposition that it destroyed Japan city by city with firebombs with or without the two nukes.
But in Aces High, particularly in Main Arena with all the other uber planes in numbers limited only by player choice, the B-29 would face much stiffer opposition and therefore do much LESS well than it did in WWII.
Play like 10 B-29s go against any assortment of 10 F-4Us, P-47s, FW-190s, La-7s, Nikis, Tempests, Typhoons. What are the odds any single B-29 would get past any single late fighter, let alone a bunch of them?
The fear of adding the B-29 to Aces High has been greatly exaggerated.